NEW YORK – Precision therapy company Blueprint Medicines said on Wednesday that it had key updates for its RET-based oncology drug programs, including top-line data from the pralsetinib trial for patients with RET-mutant medullary thyroid cancer (MTC).
The top-line data from the Phase I/II ARROW trial will support a new drug application for pralsetinib that the company plans to file with the US Food and Drug Administration in the second quarter of 2020.
Study results showed that the overall response rate to pralsetinib in 53 MTC patients who were previously treated with cabozantinib or vandetanib was 60 percent. The median duration of response was not reached at the time of data collection, and the 18-month duration of response rate was 90 percent.
The drug also had activity in treatment-naïve patients. In 19 RET-mutant MTC patients who had not received prior treatments, the overall response rate was 74 percent, with all patients experiencing tumor shrinkage. Twelve of the 14 patients who responded to treatment remained responsive to the drug for up to 15 months at the data cutoff date. Median duration of response was not reached in this group at the time.
In nine patients who had RET fusion-positive thyroid cancer, the overall response rate was 89 percent, with all patients experiencing tumor shrinkage. Seven out of eight patients who responded to the drug remained responsive for up to 20 months as of the data cutoff date. The median duration of response was not reached in this group at the time.
Blueprint Medicines recently submitted a new drug application for pralsetinib in RET fusion-positive NSCLC based on promising top-line results announced earlier this year.
Pralsetinib is an oral drug that selectively targets oncogenic RET alterations. Blueprint Medicines is developing pralsetinib for the treatment of patients with RET-altered NSCLC, MTC, and other solid tumors.
RET fusions occur in approximately 1 to 2 percent of patients with non-small cell lung cancer, 10 to 20 percent of patients with papillary thyroid cancer, and 90 percent of patients with advanced MTC. RET fusions have been observed in patients with treatment-resistant EGFR-mutant NSCLC. Currently, there are no approved therapies that selectively target RET-driven cancers.